Organic cyclic carbonates



United States Patent 3,225,063 ORGANIC CYCLE CARBONATES Gaetano F.DAlelio, South Bend, Ind, assignor to Scott Paper Company, Philadelphia,Pa., a corporation of Pennsylvania N0 Drawing. Filed May 21, 1962, Ser.No. 196,470 6 Ciaims. (Cl. 260-3402) This invention is concerned withnew foaming systems especially adapted to the production of cellulatedor expanded polymers. Generally, it deals with the synthesis and use ofnovel organic compounds, which by the interreaction of functional groupswithin the compounds, liberate carbon dioxide. When this carbon dioxideis generated within a matrix of a polymer, expanded polymer compositionsare obtained. A number of organic carbonates, such as ethylenecarbonate, propylene carbonate, glyceryl carbonate, and the like, areknown, to liberate carbon dioxide upon heating. However, the temperaturerequired to liberate the carbon dioxide from such compounds at a usefulrate is very high, and if the decomposition is performed in the presenceof a resinous polymer, pyrolysis of the polymer occurs decreasing thevalues of the physical properties of the polymers. As examples,temperatures in excess of 200 C. are required to liberate CO fromethylene-, propylene-, and glyceryl-carbonates and compounds of relatedstructure. Even at this temperature, the rate of CO liberation is toolow to be practical. It is, therefore, a primary purpose of thisinvention to synthesize organic compounds of selected structures, whichliberate CO at temperatures below 200 C., preferably at temperatureslower than about 170 C., and for practical utility, above 100 C. Thisand other objectives of the invention will become evident as thedescription of the invention proceeds.

It has been discovered that the objectives of this invention may beachieved, at least in part, by certain derivatives of the organic 1,2carbonates, which contain a free carboxyl group in their structure.These compounds will have at least one carboxyl group, COOH attachedthrough a divalent organic radical Z, to at least one 1,2 carbonatemoiety,

ing three to six carbon atoms in the chain represented by the formula HO(CH2) n l HCH2 0 II o where n is an integer having a value of one tofour or more. Thus, one class of compounds falling within the scope ofthis invention are the hemiesters of polycarboxylic acids with the 1,2carbonates of 1,2,3 propane triol; 1,2,4 butane triol; 1,2,5 pentanetriol, etc.

Such

3,225,063 Patented Dec. 21, 1965 esters are readily prepared by reactinga poly-carboxylic acid anhydride with the alcohol. Typical examples ofsuch cyclic poly-carboxylic acid anhydrides are carbon suboxide,succinic, the alkyl succinic, the halosuccinic, maleic, phthalic,itaconic, citraconic, the alkyl mercapto succinic, hexahydrophthalic,endomethylene phthalic, glutaric, l,2,4,5 benzene tetracarboxylic,acetylene dicarboxylic, etc., anhydrides. Representing the anhydrides bythe formula X(CO) O, the preparation of the half esters is in accordancewith the equation:

)3 X 0 I-IO(CH2),,CHCH1 HOOCXCOOCHzCH-|CH o\ /0 0 ll 0 A specificillustration of this reaction is the preparation of the hemi-ester ofsuccinic acid and glyceryl carbonate, thus H200 (H-12C O OH Theesterification reaction using the anhydride may be performed simply bymelting the two reactants together; but preferably to avoid thepossibility of decarboxylation, the esterification is performed in aninert solvent such as heptane, hexane, benzene, toluene, dioxane,tetrahydrofurane, etc., and isolating the product or using it dissolvedor dispersed in the reaction medium. The monoester thus formed may beused as such or as an intermediate for conversion to an alkali or alkalimetal salt of the free carboxyl group, to COOM, where M represents analkali or alkali earth metal, such as sodium, potassium, lithium,calcium, magnesium, etc.

These esters may also be prepared directly from the polycarboxylic acidin accordance with the general reaction:

HOOC-X-COOH nownanon-on,

0 0 ll nooo-X-ooo(oni Jn-orn 11,0

by heat alone, or in the presence of a small amount of an acidicesterifi-cation catalyst such as sulfuric, phosphoric, toluene sulfonic,etc., and preferably in the presence of an inert azeotroping agent, suchas benzene or toluene, to remove the water of esterificationcontinuously. By adjusting the ratio of polycarboxylic acid to thecarbonate alcohol, the amount of any di-ester, if any, is reduced to aminimum.

The COOM group required in the practice of the invention may be attachedto the CH-CH:

group in a number of other ways as through an ether linkage. Thus,alpha-chloro-propane carbonate may be reacted with a hydroxy acid, orthe alkali derivative of a hydroxy acid, such as or alternately andinversely, the alcohol may be reacted with a haloacid, thus:

ore-ou-mcmomcoom NaOl o /0 o H 0 With chloroethylene carbonate, thesubstituent group is attached directly to the ring, thus Thesubstitution may also be through a sulfur atom or a nitrogen atom, thus:

or directly through a carbon atom,

H1304 CH (iJHCH;Cl KON (|3Hi( JHoHioN w 2 o 0 II II o 0 (IJH(IJH-CHiCOOHNHAHSO o\ o o [I 0 Whereas, the cyclic carbonates, free of carboxylgroups, such as ethylene carbonate, propylene carbonate, glycerylcarbonate, chloroethylene carbonate, and alpha-chloropropene carbonateliberate CO at temperatures in excess of 200 C., any of the compoundshaving a CH -CH A moiety in combintion with a -COOM group will liberateCO at temperatures below C. regardless of the nature of the divalentradical -Z- between the two groups. The di-radical Z may, therefore, bealiphatic, including cyclo aliphatic and aromatic di-radicals, or acombination of aliphatic and aromatic structures in the diradical, andthe structure may be saturated or contain ethylenic or acetylenicunsaturation, the carbon atoms of which may be interrupted byhetero-atoms of oxygen, sulfur and nitrogen. The residual valencies ofthe carbon atoms in the di-radical -Z not occupied by the carbonateFir-(EH- o\ /o C H o and the carboxylate moieties, COOM, are occupied byhydrogen and by substituent R groups such as alkyl, aryl, alkaryl,aralkyl, alkoxy, aryloXy, carbalkoxy, acetoxy, halogeno, nitro, oxy,amino, imino, sulfo, sulfoxy, mercapto, etc. groups usually found assubstituents for H in a hydrocarbon radical. This is so, because thenature of the di-radical Z between the COOM and c112(IJH 0\ /o 0 ll 0moieties is not critical for the purposes of this invention. Thus, thefoaming agents of this invention may be simple or complex compounds, andthose compounds containmg olefinic unsaturation may be monomers such asC II 0 which are disclosed in my copending application Serial No.196,430 filed May 21,1962 and (fHC00(CH)..CH-CH1 0 which are disclosedin my copending application, Serial No. 196,484 filed May 21, 1962, bothapplications being assigned to the same assignee as the presentinvention, and to which reference is hereby made.

These compounds, as such, may be heated to cause CO generation, or theymay be used as polymers or copolymers, in which cases these monomersassume the repeating structures,

in the polymers and copolymers. To these units in the polymers, areattached polymer chains, the nature of Which depends on the number andthe kind of monomers or comonomers used in preparing the polymerizationproduct.

These polymers and copolymers, therefore, contain at least one COOMgroup and at least one CHCHr 0 0 group joined by a divalent Z radical,in the case of the itaconic half ester and in the maleic half ester,

P(iH

HP I wherein P are polymer chains which may or may not contain the samerepeating unit as the monomer. In the copolymers of vinyl acetate, the Punit will be --CH CH with styrene it is Tom-011] 0H5 with methylmethacrylate it is CHz-JJ OOCHa etc.

It is intended to include, Within the scope of this invention,therefore, polymeric as well as non-polymeric compounds containing atleast one COOM and one CHCHs group.

Polymerization and copolymers afford, then another 6 method of preparingthe compounds suitable for the practice of this invention, i.e.,compound containing at least one COOM group and at least one CHCHrgroup. This can be achieved also when the monomeric carbonate does notcontain the -COOM group by co polymerizing a second monomer containing aCOOM group with a monomer containing only groups and no COOM group.Monomers of this kind are disclosed in my copending applicationsmentioned hereinabove, and may be exemplified by the diesters ofitaconic and maleic esters of the formulas respectively. Another classof monomeric carbonates, free of COOM groups, are represented by theacrylates and methacrylates of the formula disclosed in US. Patent2,967,173, Jan. 3, 1961. By copolymerizing monomers of these types withmonomers containing a free COOM group, satisfactory polymers containingat least one COOM group and at least one group suitable in the practiceof this invention are obtained. Examples of suitable carboxylatecontaining monomers, are acrylic acid, rnethacrylic acid,alphachloroacryli-c acid, maleic acid, maleic half esters, fumaric acid,fumaric acid half esters, itaconic acid, itaconic acid half esters,alpha-cyano acrylic acid, pcyanoacrylic acid, vinyl benzoic acid, vinylhydrogen succinate, vinyl hydrogen oxalate, allyl hydrogen phthalate,etc., the requirement being that this class of comonomers contains atleast one COOM group and one polymerizable JOOCHzCHCHq Lhoocm J.

O O II iHa CH Z w CH I CHzCOOCHiCHCH: L COO Jm These polymers allliberate CO at temperatures much lower than polymers not containing--COOM groups.

The temperature at which the non-monomers, the monomeric, and thepolymeric compounds of this invention containing both COOM and moietiesliberate CO may be observed simply by heating the compounds andobserving when CO is liberated; in the case of the liquids this isassociated with bubble formation, and with the polymer with an expansionin the volume of the polymer. When the temperature is raised above thisincipient temperature, the rate of CO generation is increased accordingto thermodynamic and kinetic considerations, usually an approximatedoubling of the rate for every ten degree increase in temperature. Thus,if the temperature of incipient CO liberation is 160 C., at 200 C., theCO is liberated about 8 times faster and the time at which the foamingmixture is required to be held at this temperature is greatly reduced,thereby either eliminating pyrolysis entirely, or reducing it to a verylow and inconsequential degree.

For the production of foamed and expanded polymers the compounds of thisinvention may be added to the polymer mass before, during, or afterpolymerization, and thereafter heating to effect CO liberation. Thecompound added may be non-monomeric, or if monomeric, will become partof the polymer mass by copolymerization when added before or during thepolymerization; or if polymeric, and added before or during thepolymerization, may be converted, at least in part, to a graft polymer.Or, if the compound is polymeric and is added to another preformedpolymer, then a poly-blend foamed product is obtained. In those caseswhere the polymer itself contains -COOM and O O I! 0 groups, or where asingle monomer or a mixture of two or more monomers containing thesegroups, is heated, then internal foaming of the polymer mass occurs.

It was further discovered that the CO liberating temperature and therate of liberation of the compounds of this invention can be lowered andincreased respectively by the addition of suitable catalysts, such aszinc chloride, sodium citrate, ferrous sulfate, ceric sulfate, sodiumbicarbonate, zinc acetate, etc., as well as the alkali and alkalineearth oxide, hydroxides, carbonates, etc. In many cases, the increasedactivity is due to the catalytic effect of the intermediate compoundresulting from the neutralization of the carboxylic group by the oxide,hydroxide, carbonate or bicarbonate, thus The neutralization can beeffected before heating or may be performed while heating in thepresence of the polymer, in which case, when the carbonates are used, anadditional amount of CO is liberated, economically, in situ, for foaminguse. Other alkali salts such as sodium citrate, potassium tartrate, andmono-sodium malonate also act in a similar catalytic fashion andliberate additional amounts of CO in the process.

By selection of the appropriate compounds, a wider range ofthermoplastic polymer types can be expanded by the process of thisinvention, such as the cellulose esters, as cellulose acetate, cellulosepropionate, cellulose autobutyrate, ethyl cellulose, alkyleneterephthalate, modified alkylene terephthalate, the polyolefines such aspolyethylene, polypropylene, polybutene-l, polyalkenylaryl compoundssuch as polystyrene, polymethylstyrene, polychlorostyrene and theircopolymers, polyvinyl chloride and its copolymers, polyacrylonitrile andits copolymers, the acrylates such as polyacrylate, polymethacrylate,the polychloroacrylate, the polycyanoacrylate and their copolymers, etc.

In those cases Where the foaming agent is a monomer and is copolymerizedwith other monomers, an even wider range of polymer composition can beprepared by selection of the monomers containing polymerizable vinyl, CHCH; vinylidene, CH and vinylene, CH=CH- groups. Illustrative examples ofsuch monomers are the acrylic esters such as methyl acrylate, ethylacrylate, hexyl acrylate, phenyl acrylate, benzyl acrylate,methyl-alpha-chloroacrylate, etc.; the methacrylic esters such as methylmethacrylate, ethyl methacrylate, propyl methacrylate, octylmethacrylate, benzyl methacrylate, etc., the vinyl esters such as vinylchloride, vinyl acetate, vinyl stearate, vinyl benzoate, vinylchloroacetate, vinyl hydrogen phthalate, vinyl hydrogen succinate, etc.the polymerizable amides and nitriles such as acrylamide,hydroxymethylacrylamide, methacrylamide, itaconic monoamides, itaconicdiamide, acrylonitrile, methacrylonitrile, etc.; the alkenyl arylcompounds such as styrene, o-methyl styrene, p-methyl styrene,alphamethyl styrene, the chloro-styrenes, vinyl cyanobenzene, allylbenzene, etc.; the monoand allyl-esters such as allyl acetate, allylhydrogen succinate, allyl hydrogen phthalate, dimethyl maleate, diethyltumarate; the vinylidene compounds such as vinylidene chloride,vinylidene cyanide, methylene malonic esters, etc.; vinylene compoundssuch as vinylene carbonates, maleic anhydride, maleic and fumaricmonoesters; the itaconic compounds such as itaconic anhydride, theitaconic monoand the itaconic diesters of the lower and higher aliphaticalcohols; the dienes such as butadiene, isoprene, Z-chlorobutadiene 1,3,and the like. The proportion of the new monomers in copolymers withother monomers will depend, in accordance with the accepted principlesof copolymerization, on the reactivity and selectivity constants, r andr of the monomers used in preparing the copolymer, the ratio of themonomers used and the extent of conversion. However, by selectingappropriate conditions for the copolymerization, copolymers, using thenew monomers of this invention, can be made to contain effective andsmall amounts of these new monomers, for example, of the order of from0.1% to 0.5% to very high amounts of the order of 99.5% to 99.9% in thefinal polymer products.

The monomers used in this invention can be polymerized by the knownmethods used to polymerize acrylic, methacrylic, itaconic, or maleicmonomeric compounds. The monomers, in the presence or absence of otherpolymerizable C C containing monomers, can be polymerized in bulk,solution, emulsion, or suspension with or without polymerizationinitiators and other modifiers. As polymerization initiators there canbe used the per-compounds, such as potassium persulfate, tertiary butylperacetate, benzoyl peroxide, cumene hydroperoxide, tertiary butylperoxide, tertiary butyl perbenzoate, hydrogen peroxide with or withoutferrous salts, etc.; the azo catalysts such asalpha-alphaazobis(isobutyronitrile), ultraviolet light in the absence orpresence of ketones, ionizing radiation from X-rays electron andparticle accelerators, cobalt 60 sources, etc.

In solution polymerization the medium can be selected from solventswhich retain the polymer in solution throughout the polymerization, orcan be chosen so that the polymer precipitates when formed and can beselected from the class of aliphatic, cycloaliphatic and aromatichydrocarbons, esters, ethers, ketones, halogenated hydrocarbons, etc.;or mixtures thereof depending on the form in which the polymer isdesired. When halogenated hydrocarbons are used, they also act asmodifiers of the polymerizations. In emulsion polymerization, theemulsifying agent to be used in the aqueous system is selected from theclass of fatty acid soaps, salts of sulfonated alkyl benzenes, polyvinylalcohol, gelatin, polyacrylic acid, salts of styrene-maleic acidpolymers, gelatin and the like, which can be used alone or withbuffering agents such as sodium acetate, borax, trisodium phosphate andthe like. In suspension polymerization, the dispersion agent can beselected from the class of insoluble inorganic carbonates, phosphatesand silicates to be used alone or in the presence of minor amounts ofdeflocculating agents such as sodium dodecylbenzene sulfonate orpotassium stearate. The products obtained by solution, emulsion, orsuspension process may be used as prepared or the polymers may beisolated and further compounded with dyes, lubricants, etc, beforeheating and molding or extruding to the desired form or shape.

As indicated for the polymers and copolymers, the amount of compoundcontaining the COOM and groups used may vary from small quantities ofthe order of 0.5% to polymers of monomers having about such structure.However, depending on the molecular weight of the compound and theamount of CO desired, the lower amounts may be of the order of 1% to 5%of thtz1 total mass. When the two essential groups, COOM an CHCH2 are anintrinsic part of the polymer structure, then crosslinking of thepolymer occurs together with foaming.

The following examples illustrate the practice of this invention, andare not given by way of limitation but only in illustration. The partsand percentages used are by weight unless otherwise specified.

Example I Maleic anhydzride 73.5 parts, 88.5 parts of glycerylcarbonate,

HOOH2(IJH-(JHZ are added to 500 parts of benzene in a reaction vesselequipped with stirrer, condenser, and heating means, and the mixtureheated at 70 C. for 48 hours. Upon standing at room temperature, thedesired ester crystallizes and when separated from the benzene byfiltration will be in an almost quantitative yield. The crude ester canbe used as such or may 'be recrystallized from water. The ester producthas a melting point of 112-1 14 C.

Elemental analysis for C and H gives values of 44.96% and 3.77%respectively, which is in excellent agreement with the calculated valuesof 44.44% C and 3.70% H respectively, for the compound,4-(1,3-=dioxolone-2) methyl hydrogen maleate, corresponding to thet'ormula Example II The procedure of Example I is repeated using the 1,2carbonate of 1,2,6 hexanet-riol instead of glyceryl carbonate, and thereis obtained the corresponding maleate of the formula which on analysisfor C and H and acid number determination give values in close agreementwith the theoretical Values for the compound.

When the hexanetriol carbonate of this example is replaced by anequivalent amount of the homologous carbonates, such as 11 andHO(CHz)sCH-CH2 then the corresponding esters are obtained.

Example III 'Itaconic anhydride 84.0 parts, 88.5 parts of glycerylcarbonate,

HOCH2CH(IJH2 0 \fi/ O are added to 500 parts of benzene in a reactionvessel equipped with stirrer, condenser, and heating means, and themixture heated at 60 C. for 48 hours, following which it is cooled toroom temperature. The desired ester crystallizes on standing and isremoved from the benzene by filtration to give an almost quantitativeyield. The crude ester can be used as such or recrystallized from Water,and has a melting point of 132-134" C.

Elemental analysis for C and H and molecular weight determinations givesvalues of 46.85% and 4.57% respectively, which is in excellent agreementwith the calculated values of 47.0% and 4.35% respectively, for thecompound, 4-( 1,3 dioxolone-2) methyl hydrogen itaconate, correspondingto the formula,

Example IV The procedure of Example III is repeated using an equivalentamount of the 1,2 carbonate of 1,2,4 butanetriol instead of glycerylcarbonate, and there is obtained the corresponding itaconate of theformula placed by an equivalent amount of the homologous carbonates,such as and Ho(oH2)4oH-orn then the corresponding esters are obtained.

Example V One mole of phthalic anhydride is reacted with one mole ofglyceryl carbonate by the procedure of Example I and the isolated halfester is recrystallized from water. The melting point is 104-106 C.Elemental analysis of 12 the product gives values of 53.37% C and 3.86%H Which are in good agreement with the calculated values of 54.13% C and3.76% H for the compound, H0O? C 00OH2 |3H0H2 Example VI One mole ofsuccinic anhydride (100 parts) is reacted with one mole of glycerylcarbonate (118 parts) by the procedure of Example I, using 1100 parts ofhexane. The ester, recrystallized from benzene-ethyl alcohol mixtures,has a melting point of 101 C. Elemental analysis of the product givesvalues of 44.11% C and 4.59% H which are in good agreement with thecalculated values of 44.0% C and 4.83 H for the compound HO O CCHzCHzC OO CHzCH-CH Example VII By heating together at a temperature of from 100C. one mole of glyceryl carbonate and one mole of phathalic anhydridefor a period of 12-24 hours a product identical to that of Example V isobtained in a 100% yield.

Example VIII The melt procedure is again illustrated by the heatingtogether at a temperature of from 110 C. of one mole of glycerylcarbonate and one mole of succinic anhydride for a period of 10-22 hoursthrough which is obtained in a 92% yield a product identical to that ofExample VI.

Example IX One mole of glyceryl carbonate and one mole of allyl succinicanhydride are reacted by the procedure of Example I and there isobtained the compound One mole of glyceryl carbonate and one mole ofdodecylene succinic anhydride are reacted by the procedure of ExampleVIII and there is obtained the crude compound,

oornon -orn rnoo- 1 Example XI 13 Example XII heated until CO isgenerated in the mixture within the The procedure of Example I i t dusing 2 moles test-tube. The initial temperature of gas liberation is ofglyceryl carbonate and one mole of 1,2,4,5 benzenerecordedin Table 1-TABLE 1 TEMPERATURE OF 002 LIBERATION OF ORGANIC CYOLIC OARBONATES C.Tempera- Compound Name Structure ture of GO Elimination l. EthyleneCarbonate (FH2?H2 20 O\ /O C H O 2. Propylene Carbonate OH3CH-CH 220 O\/O C ll 0 3. Glyeerine Carbonate HOCHzCHCH: 205

O O 0 ll 0 4. Alpha-chloropropane Carbonate" CICE9CHOH2 220-225 O\ /O OH O 5. Suecinyl Glyceryl Oarbonate CHzCO OH 140 OH2C O O CHzCHCHn O O OI] O 6. Maleyl Glyceryl Carbonate CHCOOH 150-160 CH0 0 O CHZCHOH O O O HO 7. Phthalyl Glyceryl Carb0nate H 00? (I300 0120110112 125-125 0 O C HO 8. Itaconyl Glyeeryl Carbonate CH2=CCOOH 135-140 CHzC O O CH}CHCH\ O OO I O tetracarboxylic acid anhydride and there is obtained the compoundExample XIII It is readily observable that those carbonates (compounds5-8 inc.) which contain a free COOH group have a C0 eliminationtemperature lower by 50 or more degrees C. than the non-carboxylcontaining carbonates such as compounds 1-5 inc.

Example XIV Instead of prereacting succinic anhydride the glycerylcarbonate to prepare and isolate the half ester as in Example VI andthereafter heating to 140 C. as in Example XIII to release CO one moleof succinic anhydride and glyceryl carbonate are mixed and heated at140150 0., resulting in the liberation of CO together with a residualviscous resin which on continued heating becomes infusible.

Example XV One mole of succinic acid (118 parts) and one mole ofglycerine carbonate (118 parts) are mixed at room 1? temperature andthen heated until CO liberation is observed. Initial CO release occursat 140142 C., whereas the glyceryl carbonate requires a temperature ofabout 200 C. Continued heating of the mixtures leave a res inous residuesimilar to that obtained by heating the succinic half ester of ExampleXIV.

Example XVI One mole of adipic acid (146 parts) and one mole of glycerylcarbonate are mixed and heated as in the procedure of Example XV. COliberation is observed at 138l4l C., whereas glycerine carbonaterequires a temperature of about 200 C.

When 0.04 mole of adipic acid (5.9 parts) are used instead of the onemole of this example, even then the temperature of CO is reduced toabout 175 C. compared to an initial temperature of about 200 C. for theoriginal carbonate.

Example XVII To one mole of the product of Example VI in benzenealcoholmixture is added one mole of KOH dissolved in ethyl alcohol and themixture concentrated to dryness under a reduced pressure of mm. leavingas a residue the compound KOOC-CH2CH2COOCHCHOH2 O\ /O C I! O which whenheated to 150 C. liberates CO Example XVIII The succinic half ester ofExample XVI is mixed with by weight of Na CO and heated to l20-130 C.,liberating CO from the Na CO and thereafter by heating the resulting at150 0, further CO is liberated from the organic carbonate.

Instead of sodium carbonate, other carbonates such as sodiumbicarbonate, potassium carbonate, lithium carbonate, calcium carbonate,barium carbonate, and magnesium carbonate, etc., may be used as theinorganic source of CO Example XIX The maleic half ester of Example I ismixed with a number of decarboxylating catalyst and the temperature atwhich decarboxylation occurs noted and recorded as in Table 2.

l 6 Example XX One hundred parts of methyl methacrylate, 7.5 parts of4-( 1,3 di0x0lone-2) methylene hydrogen dodecylene succinate of ExampleX and 0.1 part of benzoyl peroxide are mixed and heated at 50-75 C. for72 hours or until hard and then at C. for 24 hours. On heating thepolymer at C., foaming occurs and a foamed structure is obtained oncooling to below 100 C.

Example XXI To a reaction vessel equipped with a stirrer, 350 parts ofdistilled water, 3.5 parts of hydroxy apatite, 425 parts of styrenecontaining 0.85 parts of benzoyl peroxide and 0.2 part tertiary butylperbenzoate and 0.015 part of sodium dodecylbenzene sulfonate are addedand mixed thoroughly while the system is purged with nitrogen. Thereactor is then heated to 90 C. for a period of one hour and maintainedat this temperature for 6-7 hours, following which it is heated in thecourse of one hour to 115 C. and maintained at this temperature for25-33 hours, following which it is cooled to room temperature; the beadsseparated from the water by filtration, followed 'by washing with dilutehydrochloric acid and then with distilled water. The beads may be usedin a wet condition or dried to remove the small amounts of surface waterassociated with them. Most of the beads range in the size of 10-30 mesh.Instead of the hydroxy apatite, other suspension agents such aspolyvinyl alcohol, sodium polyacrylate, the soluble salts ofstyrenemaleic anhydride polymers, etc., may be used in preparing thepolymer beads.

Example XXII Example XXI is repeated to the end of the 2.5-3 hourreaction at 115 C., following which the reaction mass is cooled to 90 C.and 45 parts of petroleum ether of boiling range 40-70 C. is added underpressure and the system maintained at 90 C. for 4-5 hours. The reactionmass is cooled to room temperature, washed with dilute hydrochloric acidand isolated as in Example XXI.

Example XXIII One hundred parts of the polystyrene as used in ExampleXXI and 5 parts of the compound of Example VI,

are dry blended and when the mixture is heated to C., a foamed polymeris obtained.

When the same composition is processed in an extruder, a continuousfoamed product is obtained. If to the mixture, before extrusion, thereis added and blended 3 parts of sodium carbonate or sodium citrate, afoamed product of lower density and of higher uniformity is obtained.

Example XXIV When the procedure of Example XXIII is repeated using thepolymer of Example XXII is an extruder equipped with a slit-die to forma thin sheet of about /8, a more uniform foamed sheet product isobtained when the monosuccinyl glyceryl carbonate, or monosuccinylglyceryl carbonate admixed with sodium carbonate or sodium citrate, isadded to the dry or wet polystyrene containing the petroleum ether.

Example XXV When the procedure of Example XXIV is repeated using the wetpolystyrene sample of Example XXI, 6 parts of the hexane dispersion ofthe organic carbonate of Example VI, and one part of sodium carbonate,foamed products similar to those of Example XXIV are obtained.

17 Example XXVI Itaconyl monoesters of glyceryl carbonate arecopolymerized with styrene, methyl methacrylate, methyl acrylate andvinyl acetate according to the procedures of Examples VI, VII, VIII, andIX of my copending application, Serial No. 196,430, (referred toherei'nabove). Each of these copolymers contains both -COOH and groupsderived from the comonomer CH =CCOOH OHzCOOCI-IzCHCHa the itaconicesters. The maleic esters copolymers also contain the -COOH and groups,and are disclosed in my copending application, Serial No. 196,430,referred to herein-above. With the maleic esters, results similar tothose of Example XXVI are obtained.

Example XXVIII Ninety three parts of styrene, parts of 2 parts ofacrylic acid are combined in 500 parts of acetone containing one part of2,2-azobisisobutyronitrile and polymerized at 6070 C. for 48 hours. Thepolymer is isolated by precipitation with methanol and dried. Heating ofthis copolymer at 150 C. causes CO liberation with crosslinking at amuch more rapid rate than in a similar copolymer containing no acrylicacid, and therefore, no COOH groups in its structure.

Substitution of the acrylic acid by methacrylic acid, vinyl benzoicacid, itaconic acid, maleic acid, fumaric acid, half esters such as themethyl ethyl, propyl, benzyl, phenyl, etc. ester of 'maleic, fumaric,itaconic, the cyanoacrylic acids, the chloroacrylic acid, etc., producea similar acceleration in the rate of CO elimination.

1 8 Example XXIX Example XXVIII is repeated using 3 parts of 0 ll 0/ \OCH2=C O 0 CH2CH(EH2 CHiC O O CHz?H-([1Hz instead of the itaconate, andsimilar results :are obtained. When styrene is replaced in Whole or inpart by other monomers, such as methyl methacrylate, dimethyl itaconate,etc., crosslinked expanded copolymers are obtained.

Example XXX When Example XXIII is repeated using plasticized celluloseacetate, cellulose-acetobutyrate, ethyl cellulose, polyvinyl acetate,plasticized polyvinyl chloride, vinyl chloride-dibutyl maleatecopolymer, vinyl chloride-vinyl acrylate copolymer,styrene-acrylonitrile copolymers, polyethylene, polypropylene,polybutene-l, ethylenepropylene copolymers, ethylene-vinyl acetatecopolymers, ethylene-acrylonitrile copolymers, modified ethyleneterephthalate, such as the succinic and adipic acid modifiedpolymerizates, polycarprolactam (Nylon 6), poly-hexamethylene adipamide(Nylon 6--6), acrylonitrile-butadiene copolymers, expanded polymericstructures are obtained.

It will be obvious that considerable variation in the component elementsof the newly discovered compounds, the manner of their preparation andutilization as foaming agents for synthetic resinous compositions arepossible without departing from the spirit of the invention or the scopeof the appended claims.

What I claim is:

1. As a new composition of matter a compound of the structureMOOC-ZCOO(CHz)nCH-CHn in which the MOOCZ-COO moiety is derived from anacid selected from the group consisting of oxalic acid, succinic acid,halo succinic acid, citraconic acid, glutaric acid, allyl succinic acid,acetylene dicarboxylic acid, alkyl mercapto succinic acid, S-acetylthiomalic acid, phthalic acid, tetrahydrophthalic acid,hexahydrophthalic acid, endomethylene tetrahydrophthalic acid, 1,2,4,5benzene tetracarboxylic acid, 3-chlorophthalic acid and 3-nitrophthalicacid, and M is selected from the group consisting of hydrogen, alkaliand alkaline earth metals and n is an integer of from 1 to 4.

2. Compound of the structure MO 0 CCHzCHaC O 0 (CH2) nCHCHI o II 0wherein M is an alkaline earth metal and n: is an integer of 1 to 4.

3. Compound of the structure Mo 0 o Gnome 0o (CH ../0H0 H,

19 20 wherein M is an alkali metal and n is an integer of 1 to 4. 6. Thecompound,

The compound, HOOC ooocmonon,

0 x, nooocmomcooomcficm Q lg References Cited by the Examiner UNITEDSTATES PATENTS 5. The compound, 10 2,628,945 2/ 1953 Wayne 260-2 52,636,884 4/1953 Tenenbaum et a1. 260-340.9 H00CQH CHICOOCHZCHCH22,737,503 3/1956 Sprague et a1. 2602.5 3,043,851 7/1962 Fischer et a1.260340.9 12112: O\ /O 15 WALTER A MODANCE, Primary Examiner. O LEON I.BERCOVITZ, Examiner.

1. AS A NEW COMPOSITION OF MATTER A COMPOUND OF THE STRUCTURE